The Dämonisch Enigma
by SwagolasThranduilion
Summary: Supernatural/Sherlock. A string of demonic murders attracts the Winchesters to the UK, while a certain consulting detective is reluctant to look at the case, until some information reaches him about the killings.
1. Boring! Wait, what?

**This is just a thing that's been floating around my mind for a little while...please, R+R :)**

**The Dämonisch Enigma**

Chapter One: "Boring!...wait, what!?"

"There's been another one, Sherlock."

Sherlock Holmes didn't even look up from his experiment to acknowledge Detective Inspector Lestrade's presence. The officer found it highly frustrating.

"Sherlock! We need you to come in on this!"

"Boring."

"What's boring about murder? I thought brutal killing was like Christmas for you!"

The consulting detective let out an exasperated sigh.

"You've obviously got a bog-standard serial killer on your hands. Surely you, the Metropolitan Police, can handle this on your own? God, I didn't think you were all _that_ dim! It's a _boring _murderer, so very uncreative, and I. Am. Not. Interested!"

"Fine. Whatever. We've got a couple of guys from across the pond anyway. They've been wanting to look into it, but I said I'd consult _you _first. Seeing as _you're _not interested, I'll hand the case over to them. FBI."

Sherlock looked at the older man, perplexed.

"Americans? Why would they be interested in a case over here?"

"No, I'm not discussing it with you any further, Sherlock."

But the younger Holmes was curious now. Never before had the FBI interfered with a British case.

"Greg, wait," Sherlock said quickly before the Inspector left, "Maybe I will…take a look…you know…just to be absolutely sure it's a boring one…"

Lestrade rolled his eyes. Sherlock Holmes, feeling threatened by a couple of yanks, that's a first!

"Right then," he stated, "New Scotland Yard, one hour."

* * *

"Tell me, why are we going to England? Also, how did you talk me into getting on a freakin' plane anyway?"

"Dean, you know as well as I do that this string of killings is demonic, you know, lightning storms, cattle mutilations…"

"Aren't there any British hunters who could handle it?"

"Dead. All of them."

Dean Winchester raised his eyebrows.

"Every single one."

He let out a low whistle.

"Demons?"

"As far as I know. Didn't you read the case file I gave you?"

Dean feigned innocence.

"Pssssh! Yeah! 'Course I did! I read the _hell _outta that thing, cover to cover-"

"Dean!"

"What? I told you, I read it!"

"Well if you _had _in fact read it, you'd know by all the vics' names that they're all hunters. They're all in dad's journal.

"Oh. Right. So, demons."

"Like I said, that's my guess. Pretty sure."

The plane shuddered, and so did the older Winchester.

"Dude, gun, mouth, now."

"You're a big baby."

* * *

"John. Come on. Murder."

"Hold on, let me get my coat, it's just in-"

"No time! Murder, John! _Murder!"_

Dr. Watson sighed, resigned.

"…Wait…I thought you weren't taking the 'boring' serial murder case?"

"There's Americans interested in it, John. FBI. I need to see what's got _them _on it!"

John understood. Sherlock couldn't have anyone stealing his thunder. He hailed a cab and the two men climbed in.

"New Scotland Yard, please."

* * *

"Hi, uh, Detective Inspector Lestrade. Agents Banner and Stark, FBI."

The brothers showed their badges.

"Gentlemen, good to meet you. Unfortunately you'll have to wait for a while, one of our…well he's not really a part of our team, as such…our consulting detective is looking at the bodies currently, you can go ahead when he's done. Please, take a seat."

The Winchesters sat as coffee was offered to each of them.

'Consulting detective?" Dean hissed, "What, are they just making up job titles now?"

"Dean, I've seen this guy's website...'The Science of Deduction'…he's a genius…like, majorly…"

"Still, I've never heard of a 'consulting detective' before…"

A new voice joined their hushed conversation, a deep baritone.

"I wouldn't expect you to have, Agent…" Sherlock narrowed his eyes, "Stark…"

The brothers' heads snapped up, taking in the lean figure in the doorway. Sam gave an awkward smile to his brother.

"Mr. Holmes! It's great to meet you, I'm a huge fan of your website, you are-"

"Orphans. Both of you. Brothers, obviously. By the way you," Sherlock motioned to Dean, "Hold yourself and the look in your eyes, you've seen bad things. Very bad things. You, tall person, not as surly as your obviously older brother. More…puppy-like. You're not FBI, you're not even police, going by your cheap suits and obviously British-made handguns, if you were FBI you'd have clearance for your own firearms. You, you were nervous on the flight over, nervous flier obviously, going by your freshly chewed nails and the crescent marks on your palms, you've been clenching your fists for some time, possibly because you're simply afraid of flying, but more likely due to the heavy turbulence on the way over the Atlantic."

"What the hell-"

"Your mother died when you were very young, your father more recently, but still a while ago. She was murdered, obviously, by the way you flinched when I mentioned her because even though it was so long ago it still hurts, so forcibly taken away from you. Your father, same situation, although you don't look upset by my speaking of him, tells me he was abusive then. Likely an alcoholic after your mother's death. Unhappy childhoods, unhappy adult lives, mostly for you 'Stark'," he turned to Sam, "You had a chance to be happy, and you were for a short while, judging by that harsh look you just shot your brother I'd say he was the one who cut your happiness short. Abusive, controlling father, created a controlling son and brother too, you wanted out, to get away, and you did, university absolutely. Being intellectual, I'd say Law, just a guess. You look sad when I mention university, in your eyes, so something must have happened, something distressing, extremely so. Going by your age, you're young, it could only possibly be a death, someone close to you, a girlfriend probably, with horrific circumstances. Shortly after, you left, not that you wanted to leave behind your education, you just couldn't live with the reminder of that event looming over you at every turn, am I wrong?"

Dean stared at him in wide-eyed shock.

"Dude…what…"

"I..-I don't even…-how…"

Sherlock smirked. Sam regained his composure.

"That was…that was one hundred per cent correct. Oh my god, I knew you were good but-"

"I'm the best."

"Oh, so modest too," Dean muttered.

Sherlock's icy gaze fixed on him. Oh crap.

"What's the point n modesty? It's stupid, I am the best at what I do and I know it. Now, your real names."

"Uh, I, um, -I'm Sam Winchester, and this is Dean…we…-we're not FBI agents, like you said…we're still investigating the murders though…"

"Why, what would normal people like you possibly know about detective work?"

Dean was done, he had had enough, more than enough.

"Listen, pal, we're gonna look at the bodies, and you're gonna shut your piehole, how about that?"

"Well that's just rude-"

"Oh my god do you hear yourself you annoying dick? Shut up already!" Dean shoved past the dark-haired man, into the morgue.

"Uh…sorry about that he's just…" Sam made an unintelligible noise, slipping past the consulting detective.

Sherlock huffed, and followed the Winchester into the morgue.

"Molly, do not let these men see the bodies they are not-"

"Shut it, buddy!" Dean held up his badge, and Sam dragged the younger Holmes out of the white room.

"FBI, Molly was it? Is that guy always so annoying?"

Molly was staring in horror after Sam and Sherlock.

"He..-he's not annoying at all…he's…-he's special-"

"Oh right, so special as in like-"

"No, no, god no, he's just different. He's a genius, he's brillian-"

"Yeah okay, so can I see those bodies or what?" Dean winked at her.

"Oh…um…n-no, I'm afraid not…Sherlock…he requested they be given back to the families immediately, the paperwork's been processed…I didn't know anyone else would want to see them I-"

"Hey, hey, calm down, it's okay, really," Dean attempted to calm the almost hyperventilating Molly Hooper, "We'll just…consult…your 'colleague'…"

"Oh he's not my colleague, he's-"

"Your boyfriend?" Dean raised an eyebrow.

"No! No, of course not, he's no one's boyfriend I-"

"So…you're single then, Molly?" Dean half-smiled.

Molly found herself become flustered, a blush rising in her cheeks.

"I…yes, I suppose I am…"

"Well, here is my card, Miss…uh…"

"Holmes! OH! I mean..-I mean Hooper…Molly Hooper…"

"Miss Hooper," Dean smiled, "You just give me a call if any more bodies like the ones before come in, okay?"

"Y-yes of course…Mr…Stark…"

Dean winked at her, flashing a toothy grin, before he turned and left.

* * *

"Did you smell it, like, as soon as we walked in?" Dean looked at his brother.

"Yeah, sulphur, super strong. We were right after all, good thing we came."

"You know," Sherlock spoke up, "I'd really appreciate if you'd let go of me, you great big brute."

Sam released the curly-haired man, who then dusted himself down.

"Tell us," Dean spoke to the consulting detective, "Anything strange about the bodies?"

Sherlock snorted.

"Other than the horrendously odious sulphuric smell? No."

"Any idea about the cause of death?"  
"Severe physical trauma, obviously."

The brothers exchanged knowing looks, and Dean nodded.

"Okay then, we have everything we need, thank you for your co-operation."

The brother exchanged another look as Sherlock studied them, bemused.

"It's not a serial killer," he said suddenly.

Sam furrowed his brow.

"Uh…of course it's a serial killer…"

"No," Sherlock's eyes gleamed, "No, if it was a serial killer you wouldn't be here. Investigative work as a hobby? Please. Who does that for fun? Well, I do, but I'm paid sometimes…you aren't getting paid, that much is obvious, so why are you here, what have I missed, OH GOD!"

The Winchesters were taken aback by the detective's sudden outburst.

"And you two, you know what's going on, how is it you know and I don't, how can you know something and I've missed it!?"

"Ha ha…well, not everyone can be right all of the ti-"

"But I AM! I am always right in my work!"

Dean smiled smugly.

"Well y-"

"I demand you tell me!" Sherlock said adamantly.

"Demons," Sam said quickly.

Sherlock took a moment to process the statement.

"…Demons…?"

"Demons."

"Okay then. How do you find demons?"

"Wait…you actually believe us? You're not gonna, I don't know, call us crazy Satanists or something?"

"I'm choosing to believe you. I have no explanation for these deaths. Once you eliminate the impossible, whatever remains, however improbable, must be the truth."

* * *

**There will be more, please review x**


	2. Ah, interesting

Chapter Two: "Ah, interesting."

"Uh...okay...we'll tell you how to track demons but uh...somewhere more private, how about that?" Dean suggested.

Sherlock sighed.

"If you insist, you do know we're in a morgue? Basically everyone's dead, how could we be anywhere more private?"

"Ah yes, 'everyone's dead', story of our lives."

Sherlock squinted at the strange remark.

"I have a feeling you'll tell me more later, yes?"

"Yeah, 'course...why are we still here?"

"Oh, we're waiting for John."

Sam tilted his head to one side, a questioning expression on his face.

"He's my associate."

Dean cracked a smile, obviously assuming a meaning completely different to what Sherlock had intended.

"Ahhh...I see, 'associate'," he nodded and winked.

"I meant no euphemism by the phrase. He's my flatmate."

Dean opened his mouth, ready to make another suggestive remark when the fair-haired doctor arrived.

"Sherlock, ready to g-" he noticed the two other men in the dimly lit hallway.

"Oh you must be the FBI guys."

"Actually John, they're-"

Once again, Sherlock was interrupted by Dean Winchester.

"Dean Stark, this is my partner, Sam Banner."

"Stark and Banner?" John scoffed, "I didn't float up the Thames in a bubble you know."

Sherlock was impressed John had caught on so quickly. The small man eyed the brothers warily.

"Sherlock?"

The consulting detective removed the smug expression from his face.

"Sam and Dean Winchester. Obviously, they're not FBI."

"Uh huh...Sherlock, can I talk to you for just a teeny tiny second?"

"We're talking now-"

John pulled Sherlock away from the two Americans, just out of earshot.

"Sherlock, what _are_ you doing?"

"Look, they know what's actually going on."

"What, the case?" John said, disbelievingly.

"Yes, and they're going to tell me -us- everything back at Baker Street. Just give them a chance."

John looked at them suspiciously again.

"Fine. But Sherlock, I swear if you get hurt I'm going to kill you."

"Promise?"

"Yeah, promise."

"Okay."

Sherlock called out to the brothers.

"Sam, Dean, come on, time waits for no man!"

* * *

221b Baker Street was rather crowed with the four men in it, the small flat barely big enough for the two living in it as it was. Sherlock stood next to the window, absent-mindedly plucking on the strings of his violin while he thought. A few moments passed before he actually spoke.

"Right. Speak. Tell me everything."

The Winchesters looked at one another.

"Uh...I don't think _everything _would be a good idea, I mean...there's a lot of freaky crap out there and it might be a bit too much..."

Sherlock fixed them with his icy glare.

"Hello, my name is Sherlock Holmes, it's my business to know what other people don't," he remarked sarcastically.

"Dude, chill. Okay. So, you know ghost stories and things like werewolves and vampires?"

The curly-haired man nodded curtly.

"Yeah well, they're all real, most of 'em. Anything anyone has ever feared, real."

Dr. Watson couldn't wrap his head around any of it. He laughed.

"You're crazy! Utterly bonkers, the pair of you! Sherlock please tell me you don't believe them?"

"I'm inclined to."

"What!?"

"Dean, demons. What are the...signs?"

"Freak electrical storms, cattle mutilation, sulphur, stuff like that. Demons possess humans and use their bodies beyond their limits, and all the victims we know of...they're like us. Hunters.

"Hunters? As in...you literally hunt these things down and dispose of them? Neat."

"Yeah pretty much."

"And the reason we're here," Sam interjected, "is because allof the British hunters are dead."

"Sorry," John interrupted, " _All_ of them?"

"Yeah," Sam replied, "There weren't many anyway, just twelve."

Sherlock stopped to think for a brief moment.

"Right then, we-"

"SHERLOCK! You can't..-can_not, _you _cannot _believe these lunatics! Oh sod this, sod. This. I'm going to get the groceries."

"Bring milk."

Dr. Watson gave his flatmate another incredulous look. He threw his hands up in frustration, and left. Sherlock sank into his chair, and turned to the Winchesters.

"Tell me everything."

* * *

Sherlock Holmes had been silent for some time. He was still processing the information he had just received.

"So everything's real. Every childhood nightmare, everything that goes bump in the night."

"More or less."

"And demons."

"Yep."

"Angels?"

Dean inhaled deeply.

"Yeah, but most of the one's we've met...well...'colossal douchebags' doesn't even begin to cover it."

"But," Sam interjected, "Not all of them. Dean, we need Cas down here anyway. Call him."

"Why's it always me who has to call him?"

"I've told you before, he listens to you, it's like...I dunno, you have a 'special something'?"

"Dude, no. Fine. I'll call him."

Sherlock was puzzled, but offered them use of his phone nonetheless.

"It's not that kind of call, buddy. Oh Castiel, I pray that you have your ears on...get your feathery ass down here before I kick it. Over."

"Hello Dean."

Sherlock jumped out of his seat, startled as the gruff voice came from behind him. He wheeled around to find himself face-to-face with a man wearing a trench coat. The man nodded to the younger Winchester.

"Sam."

"Hey Cas."

He focused his attention on the consulting detective before him, his azure eyes narrowing into slits, mimicking Sherlock's own expression.

"Hello Sherlock Holmes."

"...how do you know my name?"

"I know everyone past, present, and future's names."

"You're an angel," Sherlock simply stated, no intonation of a question in his voice.

The older Winchester coughed once.

"So uh, Cas, are you guys gonna stay standing there gettin' all cosy or...are you gonna tell us the situation here?"

Castiel sighed, stepping away from the curly-haired man and moving towards the hunters.

"There's a demon problem in this country."

Dean pursed his lips.

"Yeah, thanks, we kinda got that already. We want to know if you know what demon it is. Give us a name."

"I will need to access the victims' bodies."

Dean groaned, burying his face in his hands.

"No can do, Cas, they're gone. The only info is in his," Dean jabbed a finger at Sherlock, "Head."

"Okay."

Castiel faced Sherlock once more, stretching a hand towards him. Sherlock stepped backwards, alarmed.

"I need inside your head," Castiel stared hard at the consulting detective, who sighed and shuffled forward. Castiel reached out and pressed two fingers to his left temple. It lasted barely five seconds. His arm fell limp.

"It's a fairly young demon, I'm unfamiliar with it's...work...and that unfamiliarity means I cannot give you a name."

Sherlock suddenly realised John hadn't returned yet.

"How long has it been since John left?" he quickly asked.

Dean glanced at the clock on the wall.

"About two hours?"

Sherlock groaned.

"Ugh. Mycroft."

Castiel looked perplexed.

"Your brother?"

"Yes...he frequently kidnaps John and offers him payment to spy on me. It's been happening more since...well...you know."

Sam nodded.

"Your fake suicide?"

"Precisely."

"Ohhh-kay, that's just weird," Dean remarked, "We need to figure out who this demon is, who they're possessing, and why."

"Well," Sherlock speculated, "All the hunters in the country are dead, yes? Only two of the killings were here in London, the rest were in completely different locations? There are missing persons reports as well, did you know? I didn't think they'd be connected but knowing what I now know..."

Sherlock pulled the reports up on his laptop and handed it over to the Winchesters. Dean scanned the files.

"Nah...no 'newborn' demon is gonna want these people..they're too...I don't know...powerless? Demons almost always want power, they crave it, I can't see it being any different this ti- wait...politicians?"

Sherlock nodded.

"Yes, several politicians have been missing for a while now...although those I believe are completely unrelated to this, political assassinations you know...always played off as missing persons. It's something by brother is...seasoned...in."

"Is he a politician?"

"Not exactly...he claims he has a minor role in the British government but he _is _the British government. Mycroft can do anything really."

"Seems like you really look up to the guy."

"I hate his guts."

"Oh...th-that's nice..."

"Mmm."

"Sounds like a very happy childhood..."

"It was until Mycroft hit puberty, then he became insufferable-"

"Hello?" Sam waved his hands, "You ladies can gossip later, demon on the loose?"

They were interrupted by a disgruntled John slamming the door.

"Sherlock Holmes I am sick of your bloody brother."

"Ah John. Did you bring milk?"

Dr. Watson swept into the kitchen and dropped the carrier bag onto the table.

"Yes I got the sodding milk! Are you listening to me? Your brother. Kidnapped me. AGAIN!"

John noticed the extra man in the corner of the room.

"Who the hell's that?"

Castiel stepped forward.

"Hellp John Watson. My name is Castiel. I'm an angel of the lord."

The small doctor laughed sarcastically.

"Oh yeah? Pull the other one, it's got bells on!"

Castiel cocked his head to the left.

"I don't understand. What am I supposed to be pulling on?"

"Uh, Cas," Dean spoke up, "It's a figure of speech."

"Oh. Thank you, Dean."

"This is lovely and all," John commented, "But Sherlock, please please PLEASE tell your brother to, oh I don't know, STOP? I'm sick to the back teeth of it. And this time, he was really mean."

"Mycroft? Mean? I know he's uppity most of the time, but mean?"

"Yeah, anyway, he told me- actually demanded under pain of death- to give you this."

John pulled a sealed envelope out of his pocket and thrust it into Sherlock's hands. He began to put the groceries away, recalling something.

"You know," he said into the fridge, "For a moment I could have sworn his eyes turned black. Not that I stare at your brother's eyes or anything."

There was a sharp intake of breath from both the Winchesters. Sherlock stared down at the note in his hands.

_Come and play_

_Jim Moriarty x_

* * *

**Please review, I love feedback**_  
_

**There's more to come x**


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